[DaFace]

Originally Posted by lawrenceRaider

Crap, it's been too long since I read Warbreaker, which character crosses over?

Minor spoilers about the overall universe, but don't spoil anything about an individual book for the most part:

Spoiler!

The character that shows up in pretty much all Cosmere books is named Hoid. He's a minor character is most of the books (sometimes not even named - we only know that's who he is because Brandon has admitted it in interviews). In Warbreaker, he is a storyteller who answers a bunch of questions Siri has when she is meeting with Lightsong. He has a much larger role in the Stormlight Archive books as Wit.

But the bigger reason for reading Warbreaker first is that Vasher from Warbreaker shows up in Words of Radiance as a swordmaster named Zahel. This is irrelevant to the plot, but you notice a few things about him that seem out of place. Also, toward the end of the book, a sword shows up that greets its new holder with the phrase "Hello. Would you like to destroy some evil today?" As of this point, there's no explanation of why or how.